中矿品位大于尾矿品位，小于精矿品位。
参考答案：对
--- （on the phone）Hello, ______ Well, I can’t find her telephone number now. Can you get back to me in fifteen minutes?
--- All right, thanks!Bye-bye.
A．wait a minute.
B．hold on.
C．what for?
D．are you there?
固定电机的螺钉为（）。
A.M4*12
B.M5*10
C.M5*8
D.M5*12
